Wheel spin inhibiting apparatus



Oct. 17, 1961 J. R. EDMUND 3,004,800

WHEEL SPIN INHIBITING APPARATUS Filed 001;. 24, 1960 DIRECTION OF FREEFLOW INVENTOR. JOHN R. EDMUND 4 A WUAWE United States Patent 3,004,800WHEEL SPIN. INHIBITING APPARATUS John R. Edmund, Berkeley, Calif.,assignor to Westing house Air Brake Company, Wilmerding, Pa., acorporation of Pennsylvania Filed Oct. 24, 1960, Ser; No. 64,640 7Claims. (Cl. 303-21) This invention relates to wheel-spininhibiting'apparatus for use with railway locomotives and, moreparticularly, to control apparatus, including means responsive tospinning or slipping of a locomotive driverwheel or wheels caused byexcessive propulsion power applied thereto, for terminating suchspinning or slipping. As used hereinafter, the terms spinning orslippi'r1g will apply to that condition in which the angular rate ofspeed of a wheel, at any given instant, exceeds that corresponding tothe linear rate of speed of the vehicle.

As is well known, spinning of locomotive driver wheels often occursduring the initial efior'ts of getting a train under way, due perhaps toexcessive weight carried by.

a train of cars or to unfavorable grade or track conditions, or acombination thereof, in which case the propulsion effort applied to thelocomotivewhe'els exceeds the. resistant force offered by the adhesionorf rictio'n between the wheels and the rails. Customarily, the op:erator cuts off the propulsion power and efiects sanding of the rails toterminate-a spinning condition of the locomotive wheels, but thisvmethod is so time consuming that offtimes any momentum gained by thetrain is lost 2 a transfer valve operated by two opposingly arrangedpistons, one having a smaller pressure area than the other and operativewhen subjected to reduced main res} ervoir' pressure to move thetransfer valve toit's change.- over position in which communication isestablished via which reduced main reservoir pressure is supplied to thel brake cylinder and also to act on the larger piston.

during the time interval necessary for correcting the wheel-spinning. Ithas been found more effective to maintain the propulsion efiort on thewheels while wheel spin correction is. being effected, thus enabling thetrain to maintain maximum inertia of movement under the circumstances.In order to maintain a high degree of efii ciency,"that is, keep thetrain moving with a minimum lossiof. inertia during wheel-spincorrection, the wheel! spin condition should be corrected in as short aperiod of, time-as is possible and with the least amount of re tardingeffect on the vehicle Wheel as is necessary to tier minate wheel spinand restoremaximum tractive friction.

Accordingly, the object of this invention is to provide an apparatus'for inhibiting or correctingwheel-spin of a locomotive driver wheel or.wheels during propulsion thereof,'said apparatus being capable ofcausing said wheel or'wheels to regain maximum tractive friction, duringthe period of wheel-spin correction, without cutting off theipropulsiveeffort acting thereon and without appreciabile loss of inertial ofmotion 'already developed by the train;

1 Briefly, the, apparatus embodying the invention comprises a transfervalve device operably controlled by any suitable wheel-spin sensingdevice, responsively to a con trol impulse elfected by the wheel-spinsensing device uponoccurrence ofa spinning condition of the wheels tocause a trans-fer valve inthe valve device to be'cyclically operatedbetween a normal position, in which'a first communication isestablishedjbetween. the brake cylinder andthe brake cylinder pipe topermit normal operation of the, brakes under normal conditions, and achange-over position in which said first communication isdisestablishedand a second communication between the brake cylinder and the mainreservoir is established. The cycling action of the transfer valvedevice effects a seriesof nuid pressure impulses from the mainreservoir, at a reduced degree by the use ofa pressure limiting valve,to thebrake cylinder to cause a series of momentary retarding impulsesto be applied to the spinning wheels until thecontrol impulse elfectedby the wheel spin sensing device is-terminated by termination of" thespinning condition. The transfer'valvedevice comprises When the pressureacting on the larger piston builds up sutficiently, the transfer valveis biased back to its nor! mal position in which it remains until thepressure acting on the larger piston is gradually reduced to a value atwhich the pressure acting on the smaller pistonis again effective toshift the transfer valve to its changeoverposition. A choke device andtiming volume are- As represented by the drawing, the wheel-spininhibiting apparatus embodying the invention may comprise abrakecylinder device 1 partly cut away to expose a piston 2 and a pressurechamber 3-therein, said brake cylin der device being employed in theusual manner for operating brake shoes (not shown) associated with.vehicle driver wheels (not shown) through any suitable standard typebrake rigging fou nd on a railway locomotive. The apparatus furthercomprises a source of fiuid'under pressure in the form of a mainreservior 4 associated with the normal brake system of the locomotive, atransfer valve device 5 for controlling supply of fluid under pressurefrom reservoir 4 to the brake cylinder device 1 and release of suchpressure therefrom, .a pressure limiting device 6 interposed betweensaidmain reservoir and said transfer valve device for reducing thepressure of fluid suplied to said brake cylinder from said reservoir', atiming volume 7 of predetermined, volumetric capacity associated withsaid transfer valve device, a choke and check valve device 8 interposedbetween said trans fer valve device and said timing volume, anelectrical energizing circuit, indicated generally by the referencenumeral 9, for energizing a solenoid valve device 10 esf sociated withsaid transfer valve device, a wheel-spin sensing apparatus indicatedgenerally by the referencev numeral 11.

As shown, the apparatus 11 may be of the type' sociated with a pair ofelectric motors 12 and.13.for driving respective axles (not shown) oneach of which is mounted, at opposite ends, a pair of driver wheels (notshown) for rotation therewith, and an electro-responsive relay 14controlled by' said wheel-spin sensing apparatus for opening and closingsaid energizing cir cuit. A generator '15, driven in the usual manner asby a diesel engine (not shown), for example, provides the electricalcurrent for driving the motors 1 2 and 13.

Each associated pair of wheel-and-axle units, such as those drivenbymotors 12 and 13 respectively, (and it will be understood that theremaybe any suitable, number of such pairs on a locomotive) is providedwith a' brake cylinder, shown as brake cylinder 1, for applying andreleasing the brake shoes associated with the wheels of thecorresponding associated pair of axles.

The wheel-spin sensing apparatus 11 shown is similar to the sensingcircuit shown and described in greater detail in the locomotiveengineersOperating Manual,

Patented Oct. 17, 1961 apparatus 11 and its function will be describedherein only to an extent deemed necessary for an understanding of theinvention. Apparatus l l includes in. a sensing ci=rcuit, in addition tothe generator 15 and the motors 12 and 13, respective field coils 16 and17 for said motors, a take-off lead wire 18' from'the generator to thefield coils',and a return wire 19 from the motors to the generator. Themotorsll' and 13, with their respective series-connected field coils 16and 17, are connected in parallel relation to each other by wires 20 and21, respeot'ively. The relay 14 includes a coil 22 connected across thewires 20' and 21 by a wire 23-, said coil when energized and deenergizedacting to close and open, respectively, a switch arm 2'4 for closing andopening the energizing circuit 9," the latter circuit being providedwith'a source of directjcurrent power, such as a battery 25, forenergizing the solenoid valve devicelflassociated with the transfervalve device 5.

r The solenoid'valve device I10, which pilots operation of the transfervalve device 5, comprises a solenoid 26 connected to the energizingcircuit 9 and a valve member" 27 which is biased by a spring 28 toward anormal or seated position on a valve seat 29'for cutting oflcommunication between a passageway 30, connected by a conduit 31 to themain reservoir 4, and a passageway 32 leading to a pressure chamber 33formed in the transfer valve device 5. Bnergization of the solenoid 2oactuates the plunger type stern of valve mem er 27 to move thevalve'rhember to a' supply or unse at ed position off valve seat 29' for'establishirig communication between passageways 30' and 32Tand,therefore, between rnain reservoir 4 charriber33"via conduit 31. Anatmosphericpas sageway 34' formed in the stem of valve member 27perventing of chamber via passageway 32 when said valve member is "inits seated position. i t

"The transfenvalve device 5, withwhich the solenoid valve device 10 is"associated, comprises a casing 35 in which is'disposed'a piston valve'assemblagehaving a pilot piston 36 fixed to; one end of a spool valve37 adjacent chamber 33, said pilot pistonhaving one side or pressure as.thereof l is ss is Pr u .5 flui p evaili in sa sn 's va c r s ca 3. h vaa nlcssure ra of at e fe ive are th n h Pr sure a e of F P s i m (a lye med a y a r wdh cadedconnec'tion, to the opposite end of spool valve37,. its 5fiffi being ifis'fi d t xfl is P e s e Prevailing eontr'olchamber 3 in opposing relation to fluid p e W 9 "h P t P slqn- A pri gurges the piston-valve assemblage tqward a normal position in WW i .PlQIi P 9f 89. v lve 37 connects. an annular cavity 42 and an axiallyspaced annularcavity formed in casing 35 for placing a conduit 44, connscavity w th ham-ba f h ra yl n #35 9m isti m w th a o u 4 conn in theusual manner to a distributing. or control valve. (not 'shewn) operablycontrolled by an engineers brake ii- W wh by 51. 1 11 and release offluid under pressure to and from, respectively, the brake cylinderdevice "may be controlled; iu ihfi usual. manner, for normal brakingoperation. I i

fil masseuse is c ra le out ofits normal positiomin response to. fluidpressure. acting on the pressure face of pilot. piston 36 andprevailing.over: the combined opposing forcesv of spring, 40 and of fluid pressureacting on the pressure face of control piston 38, to a ehange-overposition in which the undercut portion 41 moves out of registry withcavity 43, to. cut oti commun-ication between conduits 45 and 44. In thechangeover position of the piston valve assemblage, the undercut portion41 is in registry with an annular. cavity. 46

formed in" casing 35 while. remaining in registry. with ealv ity 42 forplacing conduit 44 incommunication with a conduit 47. connecting saidcavity46, with main reserroir, and thereby effecting supply of fluid,pressure from said reservoir to pressure chamber 3 of the brake cylinderdevice 1. A conduit 48, in which the choke and check valve device 8 isinter-posed, connects control chamber 39 of the transfer valve device 5with conduit 44 while timing volume 7 is also connected to said controlchamher and said conduit 48, on the control chamber side of said chokeand check valve device, through a branch conduit 49.

The choke and check valve device 8 is characterized by structure thatrestricts the rate of flow of fluid under pressure therethrough in onedirection only while permitting free flow in the opposite directionindicated by the arrow in the drawing. The choke device 8, as'shown inthe drawing, comprises. a casing 50 having formed therein a circularopening 51 partly into which a cup-like check valve member 52, slidablyoperable in a guide bore 53 formed in said casing, is urged by a spring54 until said check valve member rests in a normal position against oneend of an adjusting screw 55. The adjusting screw 55 is pre-set so as toleave a precisely predetermined amount of clearance between the checkvalve member 5-2 and the circular opening 51 to permit restrictedflow-in a reverse direction to that indicated by the arrow at a ratedetermined by said clearance, the other end of said adjusting screwbeing accessible from the exterior of the casing for making the desiredsetting. The compression value of spring 54 is such as to permit thecheck valve member 52 to be readily displaced from the opening 51 bypressure of fluid flowing in the one direction indicated by the arrow,whereby flow in said one direction is unrestricted.

In normal operation, that is, during such time that no wheel-spinningoccurs, operation of the locomotive brakes is controlled in the usualmanner by the engineers brake valve (not shown), whereby supply of fluidunder pressure fr m an auxiliary reservoir (not shown) through adistributing or control valve (not shown), for example, through conduit45, valve device 5 (with valve 37 in its normal position) and conduit 44(to the brake cylinder device 1 may be effected for effecting a brakeapplication, such pressure being releasable to atmosphere back throughconduit 45 and the exhaust port of the distribut ing or control valveunder the control of said engineers brake v alve.

If wheel-spin should occur, however, such "as during initial applicationof propulsion power to the driving axles, due to some undesirable.condition, such as a wet rail, so that one pair of wheels on one of thedesignated pair of axles begins to spin, that is, said one axle rotatesat a greater rate of speed than the other axle in said designated pair,the counter electromotive output of the motor driving the spinning axleexceeds that of the motor driving the other axle. In other words,assuming that the spinning wheels are the ones on the axle driven bymotor 12,, said motor correspondingly gains in speed, as compared to thespeed of motor 13 driving the axle on the non-spinning wheelsrto set upa higher counter eleetrornotive current. Therefore, an instantaneouspotential difference at the inner terminals of the motors occurs withthe result that current flows between the two motors via wire 23 andcoil 22 or relay 14. With relay eoil 22 so energized, switch arm 24 isactuated to close the energizing circuit 9 to thereby efiectenergization of the solenoid 26 of the solenoid valve device 10.

Upon energization of solenoid 26, valve member 27 is moved to'itsunseated position in which fluid under pressure flows from mainreservoir 4 to chamber 33 of the transfer valve device 5, as abovedescribed. Pressure of fluid in chamber 33 and acting on pilot piston 36 causes valve 37 to be shifted from its normal position to itschange-over position in which chamber 3 of the brake cylinder device 1is supplied with fluid under pressure from main reservoir 4, as abovedescribed. Since the fluid. in main reservoir 4 is maintained normallyata relatively. high pressure, such as L00 p.s,i. for Qx mple,

which pressure is far in excess of that required for actuating the.brake cylinder 1 during a spinning incident of the wheels, the pressurelimiting device 6 is interposed in conduit 47 between said reservoir andtransfer valve device Sand is adjustable for reducing the pressure ofsaid fluid to a certain predetermined lower value as de sired, dependingupon the type of braking equipment with which the invention is used. Byway of example, the pressure limiting device 6 may be set to reduce thepressure to a certain value within a range of 10 to 20 psi. foreffecting a relatively light brake application on the spinning wheels.The brake application, however, is momentary in duration because in thechange-over position of valve 37 fluid under pressure from mainreservoir 4 is also rapidly supplied to chamber 39 of the transfer valvedevice 5 and to timing volume 7 by way of conduits 48 and 49,respectively, and through choke device 8, it being noted that valve 52unseats to permit such rapid flowof fluid under pressure withoutrestriction. Pressure promptly equalizes in chamber 3 of the brakecylinder device 1, in chamber 39 of the transfer valve device 5, and intiming volume 7, and when such pressure in said chamber 39 acting oncontrol piston 38 has built up sufliciently to overcome the opposingforce of fluid pressure acting on pilot piston 36, valve 37 is returnedto its normal position in which fluid pressure in the brake cylinderdevice 1 is vented to atmosphere back through conduit 45 and the exhaustport of the distributing valve (not shown) to thereby release themomentary brake application.

Fluid pressure trapped in chamber 39 of the transfer valve device 5 andin timing volume 7, however, is allowed to vent back through chokedevice 8 only at the restricted rate determined by the adjustment ofscrew 55, above described. Therefore, if, after valve 37 has returned toits normal position, a difference in the respective rates of rotation ofthe two axles in the designated pair still persists, valve member 27 ofthe solenoid valve device 10 remains in its unseated position due to thecontinuance of energization of solenoid 26 and, therefore, fluidpressure from main reservoir 4 continues to act on pilot piston 36. Thepressure acting on pilot piston 36, however, remains ineffective foragain shifting Valve 37 to its change-over position until fluid pressurein chamber 39 and timing volume 7 has reduced sufliciently to rendersaid pressure acting on said pilot piston effective for shifting valve37 to its change-over position for again effecting a momentary brakeapplication on the slipping wheel, in the manner above described.

Thus, as long as a difference in the respective rates of rotation existsbetween the two axles of the designated pair, the apparatus willfunction in a cycling fashion, as immediately above described, untilboth axles are rotating at synchronous rates of speed. It should beapparent, of

course, that it", upon completion of the first momentary brakeapplication cycle, the spinning condition has been corrected or the twoaxles are rotating at synchronous rates of speed, valve 37 will remainin its normal position since solenoid 26 will have been deenergized andvalve member 27 will have been restored to its normal position by spring28 to cut off further supply of fluid pressure from reservoir 4 tochamber 33 which is vented to atmosphere via passageways 32 and 34. Itshould also be apparent that the amount of lapsed time bet-ween eachcycle of operation of the apparatus is determined by the combinedvolumes of chamber 38 of the transfer valve device 5 and the timingvolume 7 and the setting of adjustment screw 55 of the choke device 8.

Having now described the invention, what I claim as new and desire tosecure by Letters Patent, is:

1. Vehicle brake control apparatus comprising the combination of brakecylinder means for applying a braking force to vehicle wheels, a sourceof fluid under pressure, valve means having one position to which it isyieldingly biased and in which it establishes a first communication viawhich fluid under pressure may besupplied to said brake cylinder" meansand released therefrom under manual control to effect application andrelease respectively of braking forces on the wheels, and a secondposition in which it closes said first communication and establishes adifferent communication via which fluid under pressure issuppliedfrom-said source to-said brake cylinder means, two fluid pressureresponsive means one of, which is subjectable to fluid under pressure in a chamber at one side thereof to actuate said valve means from itssaid one position to, itsjsaid second position and the other of which issubjectable to fluid under pressure in a chamber at one side thereof toexert an opposing force on said valve means which causes restora tion ofsaid valve means to its said one position, passage means providingcommunication via which fluid under pressure supplied to the brakecylinder means flows con currently to the chamber at one side of saidother fluid pressure responsive means at an unrestricted rate and viawhich fluid under pressure is released therefrom'at a restricted rateupon release of fluid under pressure from the brake cylinder meansthereby causing a cycling operation of said valve means between its saidone and said second positions so long as fluid under pressure issupplied to the chamber at one side of said one fluid pressureresponsive means, and a valve device having one position to which it isbiased and in which it releases fluid under pressure from the chamber atone side of said one fluid pressure responsive means and being operativeto a second position in which it cuts off the release of fluid underpressure from said chamber at one side of said one fluid pressureresponsive means and establishes a communication via which fluid underpressure is supplied thereto.

2. Vehicle wheel-spin inhibiting apparatus comprising the combination ofbrake cylinder means for applying a braking force to vehicle wheels, asource of fluid under pressure, valve means having one position to whichit is yieldingly biased and in which it establishes a firstcommunication via which fluid under pressure is supplied to said brakecylinder means and released therefrom under manual control to effectapplication and release respectively of braking forces on the wheels,and a second position in which it closes said first communication andestablishes :a different communication via which fluid under pressure issupplied from said source to said brake cylinder means, two fluidpressure responsive means one of which is subjectable to fluid underpressure in a chamher at one side thereof to actuate said valve meansfrom its said one position to its said second position and the other ofwhich is subjectable to fluid under pressure in a chamber at one sidethereof to exert an opposing force on said valve means which causesrestoration of said valve means to its said one position, passage meansproviding communication via which fluid under pressure supplied to thebrake cylinder means flow concurrently to the chamber at one side ofsaid other fluid pressure responsive means at an unrestricted rate andvia which fluid under pressure is released therefrom at a restrictedrate upon release of fluid under pressure from the brake cylinder meansthereby causing a cycling operation of said valve means between its saidone and said second positions so long as fluid under pressure issupplied to the chamber at one side of said one fluid pressureresponsive means, second valve means having one position to which it isbiased and in which it releases fluid under pressure from the chamber atone side of said one fluid pressure responsive means and being operableto a second position in which it cuts oif the release of fluid underpressure from the chamber at one side of said one fluid pressureresponsive means and establishes a communication via which fluid underpressure is supplied thereto, biasing means for biasing said secondvalve means toward its said one position, and wheel-spin sensing meansoperable responsively to a spinning condition of the wheels for causingsaid second valve means to be operated to said one position and totermination of said spinning condition for rendering said biasing meanseflective for restoring said second valve means to its said oneposition. v 3. The combination defined in claim 1 wherein the two fluidpressure responsive means have different respective pressure areas overwhich fluid under pressure in said chambers is effective.

- '4. The combination defined in claim -1 wherein the said other fluidpressure responsive means has a pressure area subjec'table ito fluidunder pressure in the chamber on the one side of said other flu-idpressure responsive means and larger than the pressure area of said onefluid pressure responswe means. 1 r

5. "Ih ecornbination defined in claim 1 further character'ized by aseparate timing volume of predetermined volumetric capacity connected tothe chamber at one side of said other fluid pressure responsive means.

6. The combination defined in claim 1 furthercharacterized by a checkvalve and choke device interposed in said passage means for permittingunrestricted flow of fluid under pressure to the chamber at one side ofsaid other fluid pressure responsive means concurrently with supply offluid under pressure to the brake cylinder means and for restrictingflow, in a reverse direction, of fluid under pressure from the chamberat one side of said other fluid pressure responsive means.

7. The combination defined in claim 5 further characterized by a checkvalve and choke device interposed in saidpassage means in'communicationwith said timing volume and with the chamber at one side of said otherfluid pressure responsive means for permitting unrestricted flow offluid under pressure to the chamber atone side of said other fluidpressure responsive means and to said timing volume concurrently withsupply of fluid under pressure to the brake cylinder means and forrestricting flow, in a reverse direction, of fluid under pressure fromthe chamber at one side of said other fluid pressure responsive meansand from said timing volume.

No references cited

